Concept

Torsion (algèbre)

Publications associées (20)

Correspondence functors and duality

A correspondence functor is a functor from the category of finite sets and correspondences to the category of k-modules, where k is a commutative ring. By means of a suitably defined duality, new correspondence functors are constructed, having remarkable p ...

ACADEMIC PRESS INC ELSEVIER SCIENCE2023

DARKFLUX: A new tool to analyze indirect-detection spectra of next-generation dark matter models

Emma Elizabeth Tolley

We present DARKFLUX, a software tool designed to analyze indirect-detection signatures for next-generation models of dark matter (DM) with multiple annihilation channels. Version 1.0 of this tool accepts user-generated models with 2 -> 2 tree-level dark ma ...

ELSEVIER2022

Subgroups of elliptic elements of the Cremona group

Christian Lucius Urech

The Cremona group is the group of birational transformations of the complex projective plane. In this paper we classify its subgroups that consist only of elliptic elements using elementary model theory. This yields in particular a description of the struc ...

2021

Extensive amenability and a Tits alternative for topological full groups

Nóra Gabriella Szoke

This dissertation investigates the amenability of topological full groups using a property of group actions called extensive amenability. Extensive amenability is a core concept of several amenability results for groups of dynamical origin. We study its pr ...

EPFL2019

Experimental investigation of beams under coupled bending and torsion

Corentin Jean Dominique Fivet, Nicolas Robin Montagne, Olivier Baverel

The design of doubly-curved systems called for innovative modelling techniques to evaluate the final geometry of the structure. They can simulate the behaviour of beams under large displacements. Even though it is never analysed, the deformation path is ca ...

International Center for Numerical Methods in Engineering (CIMNE)2019

Some consequences of Masser's counting theorem on elliptic curves

Valéry Aurélien Mahé

We use Masser's counting theorem to prove a lower bound for the canonical height in powers of elliptic curves. We also prove the Galois case of the elliptic Lehmer problem, combining Kummer theory and Masser's result with bounds on the rank and torsion of ...

Springer Heidelberg2017

Virtual Submodule Concept for Fast Semi-Numerical Modular Multilevel Converter Loss Estimation

Drazen Dujic, Alexandre François Christe

During the design phase of a modular multilevel converter (MMC), an accurate loss evaluation of the submodule (SM) plays an important role. In this paper, a method based on the analytical description of the MMC key waveforms that allows to directly obtain ...

Institute of Electrical and Electronics Engineers2017

Isogeny graphs of ordinary abelian varieties

Dimitar Petkov Jetchev, Benjamin Pierre Charles Wesolowski, Ernest Hunter Brooks

Fix a prime number l. Graphs of isogenies of degree a power of l are well-understood for elliptic curves, but not for higher-dimensional abelian varieties. We study the case of absolutely simple ordinary abelian varieties over a finite field. We analyse gr ...

Springer Heidelberg2017

The torsion group of endotrivial modules

Jacques Thévenaz

Let G be a finite group and let T(G) be the abelian group of equivalence classes of endotrivial kG-modules, where k is an algebraically closed field of characteristic p. We determine, in terms of the structure of G, the kernel of the restriction map from T ...

Mathematical Science Publ2015

The homotopy theory of coalgebras over a comonad

Kathryn Hess Bellwald

Let K be a comonad on a model category M. We provide conditions under which the associated category of K-coalgebras admits a model category structure such that the forgetful functor to M creates both cofibrations and weak equivalences. We provide concrete ...

2014

On the topological full group of a minimal Cantor Z2-system

Nicolas Monod, Gábor Elek

Grigorchuk and Medynets recently announced that the topological full group of a minimal Cantor Z-action is amenable. They asked whether the statement holds for all minimal Cantor actions of general amenable groups as well. We answer in the negative by prod ...

2013

Fixed points and amenability in non-positive curvature

Nicolas Monod

Consider a proper cocompact CAT(0) space X. We give a complete algebraic characterisation of amenable groups of isometries of X. For amenable discrete subgroups, an even narrower description is derived, implying Q-linearity in the torsion-free case. We est ...

Springer2013

The valuation criterion for normal basis generators

If L/K is a finite Galois extension of local fields, then we say that the valuation criterion VC(L/K) holds if there is an integer d such that every element x is an element of L with valuation d generates a normal basis for L/K. Answering a question of Byo ...

2012

Prym varieties of spectral covers

Tamás Hausel

Given a possibly reducible and non-reduced spectral cover pi: X -> C over a smooth projective complex curve C we determine the group of connected components of the Prym variety Prym(X/C). As an immediate application we show that the finite group of n-torsi ...

Geometry & Topology Publications2012

Le foncteur de bi-ensembles des modules de p-permutation

Mélanie Baumann

Let k be an algebraically closed field of characteristic p, where p is a prime number or 0. Let G be a finite group and ppk(G) be the Grothendieck group of p-permutation kG-modules. If we tensor it with C, then Cppk becomes a C-linear biset functor. Recall ...

EPFL2012

Endotrivial modules for p-solvable groups

Jacques Thévenaz, Nadia Mazza

We determine the torsion subgroup of the group of endotrivial modules for a finite solvable group in characteristic p. We also prove that our result would hold for p-solvable groups, provided a conjecture can be proved about the case of p-nilpotent groups. ...

2011

On growth and torsion of groups

We give a subexponential upper bound and a superpolynomial lower bound on the growth function of the Fabrykowski-Gupta group. ...

2009

Prediction of the twisting moment and axial force in a circular rubber cylinder for combined extension and torsion based on the logarithmic strain approach

Anastasios Vassilopoulos

The scope of the present work is the application of a particular class of strain energy function, based on the logarithmic strain, for the prediction of the twisting moment and axial force of a rubber circular cylinder under combined extension and torsion. ...

2008

What static and dynamic properties should slalom skis possess? Judgments by advanced and expert skiers

Michael Herzog, Olaf Blanke, Pierre-Etienne Bourban, Christian Fischer

Flexural and torsional rigidity are important properties of skis. However, the flexural and torsional rigidity that lead to optimal performance remain to be established. In the present study, four pairs of slalom skis that differed in flexural and torsiona ...

Taylor & Francis2007

The classification of torsion endo-trivial modules

Jacques Thévenaz

The main purpose of this paper is to show that, if G is a finite p-group which is not cyclic, quaternion or semi-dihedral, then the group of endo-trivial G-modules is detected on restriction to elementary abelian p-subgroups of rank 2. Consequently, the to ...

2005